Linux I/O Scheduler is a process of accessing the block I/O from storage volumes. I/O scheduling is sometimes called disk scheduling. Linux I/O scheduler works by managing a block device’s request queue. It selects the order of requests in the queue and at what time each request is sent to the block device. Linux I/O Scheduler manages the request queue with the goal of reducing seeks, which results in great extent for global throughput.
There are following I/O Scheduler present on Linux:
1. noop – is often the best choice for memory-backed block devices
2. cfq – A fairness-oriented scheduler. It tries to maintain system-wide fairness of I/O bandwidth.
3. Deadline – A latency-oriented I/O scheduler. Each I/O request has got a deadline assigned.
4. Anticipatory – conceptually similar to deadline, but with more heuristics to improve performance.
To View Current Disk scheduler:
```
# cat /sys/block/<Disk_Name>/queue/scheduler
```
Let’s assume that , disk name is /dev/sdc, type:
```
# cat /sys/block/sdc/queue/scheduler
noop anticipatory deadline [cfq]
```
### To change Linux I/O Scheduler For A Hard Disk:
To set a specific scheduler, simply type below command:
